The major active constituents in linden are flavonoids, glycosides, and possibly a volatile oil. One study found that a complex mixture of compounds, primarily flavonoids, reduced anxiety in mice.³ Although used as a traditional herbal remedy for anxiety, these results have not been confirmed in human clinical trials. Older clinical trials have shown that linden flower tea can help people with mild gallbladder problems (but not gallstones), upset stomach or dyspepsia, and excessive gas that causes the stomach to push up and put pressure on the heart (also known as the gastrocardiac syndrome.)^{4, 5} Linden’s reputed antispasmodic action, particularly in the intestines, has been confirmed in at least one human trial.⁶

Linden flowers act as a diaphoretic when consumed as a hot tea. Diaphoretics induce a mild fever, thereby possibly helping promote the immune system’s ability to fight infections. The fever usually does not go very high because the diaphoretic also causes sweating, the body’s natural way of lowering its temperature. The German Commission E has approved linden flower for the treatment of colds and cold-related coughs.⁷